The present invention relates to rolls for use as withdrawal rolls in continuous casting machines.
Rolls of this type engage an ingot as it is withdrawn from the casting machine, and the ingot is, of course, quite hot at that point. Thus, it is necessary to cool the rolls extensively. While external spray water cooling of the ingot will inherently cool also the rolls from the outside, internal cooling of the rolls is quite necessary to avoid too rapid a wear of them.
Water-cooled rolls as they are used are constructed to circulate water through internal ducts. It was found now that due to gravity aided by a considerable vapor pressure air pockets are produced in upper portions of the ducts or duct system. Bearing in mind that these rolls have horizontal axes, it will be observed that some rolls support an ingot as veered towards the horizontal, from below. Thus, such a roll may engage a hot ingot with surface portions underneath and inside of which happens to be such an air-pocket, causing insufficient cooling of that particular roll portion which actually needs cooling the most.